_RP_1632-1996_2010.pdf

Cathodic Protection of Underground Petroleum Storage Tanks and Piping SystemsAPI RECOMMENDED PRACTICE 1632THIRD EDITION,MAY 1996REAFFIRMED,DECEMBER 2010 Cathodic Protection of Underground Petroleum Storage Tanks and Piping SystemsManufacturing,Distribution and Marketing DepartmentAPI RECOMMENDED PRACTICE 1632THIRD EDITION,MAY 1996REAFFIRMED,DECEMBER 2010 SPECIAL NOTES API publications necessarily address problems of a general nature.With respect to par-ticular circumstances,local,state,and federal laws and regulations should be reviewed.API is not undertaking to meet the duties of employers,manufacturers,or suppliers towarn and properly train and equip their employees,and others exposed,concerning healthand safety risks and precautions,nor undertaking their obligations under local,state,orfederal laws.Information concerning safety and health risks and proper precautions with respect toparticular materials and conditions should be obtained from the employer,the manufac-turer or supplier of that material,or the material safety data sheet.Nothing contained in any API publication is to be construed as granting any right,byimplication or otherwise,for the manufacture,sale,or use of any method,apparatus,orproduct covered by letters patent.Neither should anything contained in the publication beconstrued as insuring anyone against liability for infringement of letters patent.Generally,API standards are reviewed and revised,reafrmed,or withdrawn at leastevery ve years.Sometimes a one-time extension of up to two years will be added to thisreview cycle.This publication will no longer be in effect ve years after its publicationdate as an operative API standard or,where an extension has been granted,upon republica-tion.Status of the publication can be ascertained from the API Authoring Departmenttelephone(202)682-8000.A catalog of API publications and materials is publishedannually and updated quarterly by API,1220 L Street,N.W.,Washington,D.C.20005.This document was produced under API standardization procedures that ensure appro-priate notication and participation in the developmental process and is designated as anAPI standard.Questions concerning the interpretation of the content of this standard orcomments and questions concerning the procedures under which this standard was devel-oped should be directed in writing to the director of the Authoring Department(shown onthe title page of this document),American Petroleum Institute,1220 L Street,N.W.,Wash-ington,D.C.20005.Requests for permission to reproduce or translate all or any part of thematerial published herein should also be addressed to the director.API publications may be used by anyone desiring to do so.Every effort has been madeby the Institute to assure the accuracy and reliability of the data contained in them;how-ever,the Institute makes no representation,warranty or guarantee in connection with thispublication and hereby expressly disclaims any liability or responsibility for loss or dam-age resulting from its use or for the violation of any federal,state,or municipal regulationwith which this publication may conict.API standards are published to facilitate the broad availability of proven,sound engi-neering and operating practices.These standards are not intended to obviate the need forapplying sound engineering judgment regarding when and where these standards shouldbe utilized.The formulation and publication of API standards is not intended in any way toinhibit anyone from using any other practices.Any manufacturer marking equipment or materials in conformance with the markingrequirements of an API standard is solely responsible for complying with all the applica-ble requirements of that standard.API does not represent,warrant,or guarantee that suchproducts do in fact conform to the applicable API standard.All rights reserved.No part of this work may be reproduced,stored in a retrieval system,or transmitted by any means,electronic,mechanical,photocopying,recording or other-wise,without prior written permission from the publisher.Contact the Publisher,API Publishing Services,1220 L Street,N.W.,Washington,D.C.20005.Copyright 1996 American Petroleum Institute FOREWORD This recommended practice describes the corrosion problems characteristic in under-ground steel storage tanks and piping systems and provides a general description of thetwo methods currently used to provide cathodic protection against corrosion.Persons planning to construct an underground storage facility,replace existing under-ground storage tanks and piping systems,or cathodically protect existing undergroundstorage tanks and piping should refer to applicable local,state,and federal re,safety,andenvironmental regulations as well as the following publications:a.API RP 1615.b.API RP 1621.c.NACE RP-01-69.d.NACE RP-02-85.e.NFPA 30.f.NFPA 70.g.PEI RP100-87.At the time this recommended practice was written,legislation and regulations relatedto the design,installation,operation,and maintenance o